ASPEN, Colo. — The state of the international political landscape is more unpredictable and uncertain now than it has been in 38 years.

That’s according to Gen. Raymond T. Odierno, the Army’s chief of staff, who spoke at the opening session of the Aspen Security Forum last week.

Odierno answered questions from The New York Times reporter David E. Sanger about national security, international politics and the future of the Army.

The state of world politics has come to a head in recent weeks with crises breaking out in the Ukraine, Israel, Syria, Iraq and Afghanistan.

“Since 2012, the world has not become a safer place,” Odierno said.

Odierno attributed the recent surge in violence to the fact that many of the countries facing upheaval are tied together politically.

Most of the problems in Iraq that occurred since the U.S. pulled out troops stemmed from a lack of leadership. The leaders were replaced and that led Iraqi soldiers to question their purpose, causing some to defect. That essentially opened the door for the extremist group, known as the Islamic State in Iraq and Syria, he said.

“The lesson I learned was that military power cannot solve problems alone,” Odierno said.

As for the crisis in Syria, that would have happened no matter what the U.S. had done, he said.

Odierno said the U.S. should pay close attention to the crisis in Ukraine and support the National Atlantic Treaty Organization.

“Militarily, it’s a bit of a wake-up call for NATO,” Odierno said.

Still, he said the U.S. should be careful before getting involved, because the issue is complex.

Meanwhile, the federal government’s budget sequestration of 2013 has threatened to cut the size of the current Army. If personnel is cut further, Odierno will have to reevaluate the nation’s current strategy, he said.

Ultimately, Odierno doesn’t want to see a draft occur, but that could be triggered by a budget shortfall, he said. The Army today is more capable than the Army in the past because soldiers are better trained and serve longer than previous generations, which makes them more experienced, Odierno said.

“I think it’s worth the investment,” Odierno said of the voluntary Army.